36 Transfusion medicine Flashcards
What is a unit of RBC?
How is it prepared? (4)
Concentrated red blood cells.
Plasma removed and replaced with glucose, electrolytes and adenine.
How is a unit of RBC stored?
4 degrees for up to 35 days.
How is a unit of RBC administered?
Over 1.5-3 hours.
4 hour time limit from cold removal and end of transfusion.
What is the transfusion threshold?
Lowest threshold of haemoglobin not associated with symptoms of anaemia.
How does the body adapt to anaemia? (6).
Increased cardiac output. Increased coronary artery flow. Increased oxygen extraction. Increased 2,3-DPG levels. Increased EPO production. Increased erythropoiesis.
What does tissue oxygenation depend on?
Concentration of haemoglobin.
What is the trigger for blood transfusions in anaemia?
Less than 70g/L with mild symptoms.
Less than 80g/L with CV disease.
When should blood transfusion take place in anaemia from acute blood loss?
More than 30% of blood volume or more than 1500mL lost.
What is the aim of blood transfusion in chronic ischaemia due to myeloid failure? (3)
Symptomatic relief.
Improvement in quality of life.
Prevention of ischaemic organ damage.
What is the aim of blood transfusion in chronic ischaemia due to inherited anaemia?
Suppression of endogenous erythropoiesis.
Target: 100-120 g/L.
How are platelets stored and used?
Room temperature for 5 days from collection.
Transfusion over 30 minutes.
When should platelets be transfused?
Treat bleed due to severe thrombocytopenia or platelet dysfunction.
Prevention of bleeding.
What are the contra-indications for platelet transfusion?
Heparin indued thrombocytopenia and thrombosis.
Thrombotic thrombocytopenia purpura.
How is fresh frozen plasma stored and administered?
-30 degrees for up to 24 months.
Thawed before used, transfused over 30 minutes.
When should fresh frozen plasma be transfused? (3)
Coagulopathy with bleed/surgery.
Thrombotic thrombocytopenia purpura.
Massive haemorrhage.
What is the treatment for life-threatening bleeding in Warfarin overdose?
Prothrombin complex concentrate.
Plasma-derived Vit K dependent factors: II VII IX X.
When should CMV negative blood products be used?
Children under 1
Intrauterine tranfusion
Congenital immunodeficiency
Pregnant women (unless known +ve)
When should irradiated blood products be used? (5)
Intrauterine transfusions. Congenital immunodeficiency. Hodgkin Lymphoma. Stem cell / marrow transplant patients. After purine analogue chemo.
What is the pathogenesis of acute haemolytic reaction-ABO incompatibility? (4)
Deposition of Hb in renal tubules causes renal failure.
Stimulation of cytokine storm.
Microvascular thrombosis.
Generalised vasoconstriction mediated by NO.
What is group and screen?
ABO and Rh group identification.
Screening for other major blood group antigens.
What is cross-matching?
Donor selected with correct ABO, Rh and antibodies.
Some of donor and patient blood mixed to see if reaction occurs.
What are the immunological acute transfusion reactions? (3).
ABO incompatibility.
Allergic reaction.
TRALI (transfusion related acute lung injury).
What are the non-immunological acute transfusion reactions? (3).
TACO (transfusion associated circulatory overload).
Bacterial contamination.
Febrile non-haemolytic transfusion reaction.
What are the delayed transfusion reactions?.
2 immunological.
1 non immunological.
Transfusion associated graft vs host disease. Post transfusion purpura.
Transfusion transmitted infection (viral/prion).
Which risk is great: transfusion transmitted infection or the wrong blood product being given?
Wrong blood product.
What are the symptoms of acute haemolytic reaction ABO incompatibility? (7)
More severe within 15mins. Fever Back, chest, and infusion pain Hypotension /shock Hemoglobinuria Increased bleeding (DIC) Sense of “impending death”
What is the pathogenesis of delayed haemolytic reaction?
Antigens form after transfusion toe RBC antibodies that aren’t ABO.
When does a delayed haemolytic reaction present?
Symptoms? (3)
Bloods? (3)
3-14 days post transfusion.
Fatigue, jaundice, ± fever.
Drop in Hb. Increased LDH and indirect bilirubin.
What is Coomb’s test?
Anti-human globulin test.
Test for incomplete IgG antibodies.
What is transfusion related lung injury?
How does it occur?
Acute lung injury within 6hrs of transfusion.
Donor antibodies to recipient leukocytes - activated WBC lodge in capillaries + damage them.
What is acute lung injury?
Hyperaemia.
New bilateral CXR infiltrates.
No evidence of volume overload.
How is TRALI treated?
Supportive: O2, or mechanical ventilation.
What the presentation of transfusion related circulatory overload (TACO)? (7)
Sudden dyspnoea Orthopnea Tachycardia Hypertension Hyperaemia. Raised JVP and BP.
What are the risk factors for TACO? (3)
Elderly or young.
Compromised left ventricular function.
Increased volume or rate of transfusion.
What are the two types of allergic reaction seen from transfusion?
Urticarial rash.
Anaphylaxis.
What is a febrile non-haemolytic transfusion reaction?
What is the cause?
Management?
Fever, ± shakes, rigors, increased pulse.
Not life threatening.
Due to accumulation of cytokines during storage.
Discontinue transfusion until wrong blood/infection excluded.
